I found some data on the first names parents gave their children in 2004 (data from statbel.fgov.be). It should come as no surprise that passe-partout names (used in both Dutch and French) dominate the first names hitparade.

Here are the top 10 per province for the girls:
Meisjesnamen in Belgie 2004

Popular names in Belgium in 2004? Timeless names like Emma, Marie, Julie, Chloé. And some currently-in-fashion-names: Febe, Océane, Amber. You meet a girl in 2030 whose name is Febe? “You must be something like … 25?”

I did another exercise: within the Dutch speaking (‘Flemish’) provinces, what are the top names that are local to that province only?
Vlaamse meisjesnamen 2004

Antwerp: Imane, Caro, Yousra, Anissa, Yasmina
“Caro” is a trendy name, that had its peak in 1999 and is already on the way down (check Wegenerdm.be for details), and “Yousra” the same. “Imane” is a common first name since 1993, “Anissa” has been popular since the mid 80s, and Yasmina even a bit longer. (Remark: the numbers for Brussels are NOT included in this last calculation, otherwise I’m sure there would have been Yasminas in Brussels, and as such it would not be a name local to only Antwerp)
Limburg: Dilara, Anne, Beyza, Elisabeth, Ilayda
“Dilara” and “Beyza” are a favourite amongst Morrocon parents since 1995, but “Ilayda” is a very recent fad (since 2000). “Anne” is a classic Dutch name (peak around ’50-’70). Elizabeth is a real timeless name: has never been wildly popular, but has never disappeared either.
Oostvlaanderen: Iris, Phebe, Ashley, Saar, Tiany
Phebe looks like a variant of the #10 of that province “Febe”. The name “Ashley” can probably be credited to some Australian soap opera, and Tiany makes me thinks of the Pfaffs. “Iris” has not been out of fashion since ’70, and “Saar” is younger: started in ’80.
Vlaams Brabant: Clara, Inès, Léa, Zoé, Rune
What’s with the accents already? A clear influence of French-speaking inhabitants here. Rune is the only Flemish name (of Celtic origin?), and was quasi non-existent five years ago.
West-Vlaanderen: Auke, Evy, Gaëlle, Hayley, Margo
“Auke” sounds like a name that was blown over from Holland (around 2000) and “Evy” was a fad around 1980 (with Evy Gruyaert and Evi Hansen as pretty examples). “Gaëlle” sounds so French, maybe an influence from our southern neighbors. “Hayley” – who calls their kid Hayley … – anyone has an idea where this could come from? “Margo” is the Dutch variant of “Margot”, a name that has been extremely popular since 1990.

If you plan on having kids: the raw numbers from statbel are a goldmine!